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San Antonio Water System Standard Specifications for Construction
852-1 August 2019 852 sanitary sewer manhole.docx
ITEM NO. 852
Sanitary Sewer Manholes
852.1 DESCRIPTION: This item shall govern the construction of standard sanitary sewer
manholes complete in place and the materials therein, including manhole rings and
covers. All material and construction work shall be in accordance with current Texas
Commission on Environmental Quality (TCEQ) rules to include: Design Criteria for
Sewage Systems (30 TCEQ § 217) and Chapter 213 Edwards Aquifer Recharge Zone,
or any revision thereto as applicable.
852.2 REFERENCED STANDARDS: Reference standards cited in this Specification Item No. 852
refer to the current reference standard published at the time of the latest revision date logged at the
end of this Specification Item No. 852, unless a date is specifically cited.:
1. San Antonio Water System (SAWS):
a. Specifications for Water and Sanitary Sewer Construction
b. SAWS Materials Specifications
2. City of San Antonio (COSA) Specifications for Construction
3. Texas Commission of Environmental Quality (TCEQ)
a. Chapter 217 Design Criteria for Domestic Wastewater Systems
b. Chapter 213 (“Edwards Aquifer”)
4. AASHTO – American Association of State Highway and Transportation Officials:
a. M306: Standard Specification for Drainage, Sewer, Utility, and Related
Castings.
5. ASTM – American Society for Testing and Materials:
a. ASTM A 307 - Standard Specification for Carbon Steel Bolts and Studs,
60,000 psi Tensile
b. A536: Standard Specification for Ductile Iron Castings.
c. ASTM A 615 - Standard Specification for Deformed and Plain Billet-Steel
Bars for Concrete Reinforcement
d. ASTM C 443 - Standard Specification for Joints for Circular Concrete
Sewer and Culvert Pipe, Using Rubber Gaskets.
e. ASTM C 478 - Standard Specification for Precast Reinforced Concrete
Manhole Sections
f. ASTM C 890 - Standard Practice for Minimum Structural Design Loading
for Monolithic or Sectional Precast Concrete Water and Wastewater
Structures
g. ASTM C 913 – Standard Specifications for Precast Concrete Water and
Wastewater Structures.
h. ASTM C 990 – Standard Specification for Joints for Concrete Pipe,
Manholes, and Precast Box Sections Using Preformed Flexible Joint
Sealants
i. ASTM D638: Test Method for Tensile Properties of Plastics.
San Antonio Water System Standard Specifications for Construction
852-2 August 2019 852 sanitary sewer manhole.docx
j ASTM D648: Standard Test Method for Deflection Temperature of Plastics
under Flexural Load in the Edgewise Position. k ASTM D 698 - Standard Test Method for Laboratory Compaction
Characteristics of Soil Using Standard Effort (12,400 ft-lb/ft.)
l ASTM D790: Flexural Properties of Unreinforced and Reinforced Plastics
and Electrical Insulating Materials.
m ASTM D1238: Standard Test Method for Melt Flow Rates of
Thermoplastics by Extrusion Plastometer.
n ASTM D1505: Standard Test Method for Density of Plastics by the
Density-Gradient Technique.
o ASTM D1693: Standard Test Method for Environmental Stress-Cracking
of Ethylene Plastics.
p. ASTM D 2665 - Standard Specification for Poly (Vinyl Chloride) (PVC)
Plastic Drain, Waste and Vent Pipe and Fittings
q ASTM D 2996 - Standard Specification for Filament-Wound “Fiberglass”
(Glass-Fiber-Reinforced Thermosetting-Resin) Pipe
r. ASTM D 2997 - Standard Specification for Centrifugally Cast “Fiberglass”
(Glass-Fiber-Reinforced Thermosetting Resin) Pipe
6. American Society of Mechanical Engineers
a. ASME B 16.1 - Cast Iron Pipe Flanges and Flanged Fittings
852.3 SUBMITTALS: Contractor shall submit manufacturer’s product data, instructions,
recommendations, shop drawings, and certifications. All submittals shall be in accordance
with Engineer’s requirements, and submittals shall be approved by the Engineer prior to
delivery.
1. Submit proposed methods, equipment, materials and sequence of operations for
sewer construction.
2. Plan operations so as to minimize disruption of utilities to occupied facilities or
adjacent property.
3. Submit test reports
4 Submit pre and post construction videos. Videos become property of SAWS.
852.4 MATERIALS: All constructed manholes shall be watertight and equipped with pre-
tested and approved ring and covers. Sewer manhole ring and cover castings shall meet the
current requirements of the American Association of State Highway and Transportation
Officials (AASHTO) Designation M306-10. 1. Concrete Manhole Components: For new concrete manholes, all concrete manhole
components (cast-in-place or precast manhole base, precast risers, precast cone
sections, cast-in-place or precast flat tops, and as applicable) for new manholes
shall conform to the applicable requirements of ASTM Designation C478, except
as modified below.
a. Concrete Grout: All concrete grout used for patching or other similar fill-in
work shall be of non-shrink type made with the Komponent® admixture
specified above, or approved alternate, in accordance with the
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852-3 August 2019 852 sanitary sewer manhole.docx
manufacturer’s recommended formulation with Portland cement, fine aggregate, water, and water reducer to produce a compressive strengths of
approximately 4,800 psi within 7 days and 7,250 psi within 28 days at a 70
⁰F baseline temperature.
2. The manhole ring and cover shall be of ductile iron or gray cast iron construction.
The cover shall be solid with no vent or pick holes; hinged with underlying special
hinge area leakage protection; the cover secured with four (4) stainless steel bolts;
and shall have a recessed “pick bar” for cover opening. Cam lock type covers shall
not be allowed.
a. Approved manufacturers, as listed in the SAWS Approved Products List
(APL), have previously completed required inflow leakage shop testing and
have met a maximum allowable leakage rate criterion of 1 gallon per minute
(gpm) at 12 inches of water submergence above the manhole cover.
b. Nominal cover diameter shall be 32 inches, with 30 inch clear opening, as
required by TCEQ
c. 24-inch covers to be utilized on existing manholes with 24 covers only
d. Vented Manhole Covers will be specified by SAWS Engineer.
3. “Throat rings” shall be made of HDPE and have a maximum thickness of 2 inches.
No concrete throat rings shall be used.
a. The internal diameter shall match that of the ring and cover’s opening.
"HDPE “throat rings” are to be used in conjunction with a UV stabilized
internal polyethylene liner for the purpose of providing an
infiltration/inflow (I/I) barrier.
b. The I/I Barrier shall be as manufactured by Strike Tool Products of Cannon
Falls, MN. See SAWS APL.
c. Note of Clarification: A minimum of two and a maximum of six “throat
rings” may be used at each adjusted manhole. “Throat rings” are limited to
a minimum of two and a maximum of four rings for new manhole
construction. Throat rings shall be a maximum thickness of two (2) inches.
4. Bitumastic Joint Sealant. Flat tops, and between the ductile or gray cast iron ring
(frame) and the uppermost adjustment ring or flat top: See Approved APL.
5. Interior Coating: The interior of all rehabilitated manholes shall be rendered
watertight, chemically resistant, and abrasion resistant through the use of a SAWS
approved sewer coating. See SAWS APL
a. Prior to coating, all manholes shall be hydrostatic test and/or vacuum tested,
and approved by Inspector or Engineer.
b. Contractor shall follow manufacturer’s recommendations in manhole
preparation and product application to ensure that coating systems properly
adhered to manhole walls and to prevent moisture from entering behind
coating
c. Coating shall be applied to the interior of the manhole to the top of the cone
section and extend 6-inches down the exterior side of the cone section. See
Drawing DD-852 drawing series.
d. Note of Clarification: Existing manholes being adjusted only as per
San Antonio Water System Standard Specifications for Construction
852-4 August 2019 852 sanitary sewer manhole.docx
Specification Item 851 will not require a coating system.
6. For rehabilitated manholes; first, apply a combination of cementitious coatings
followed by an approved epoxy coating. Kerneos SewperCoat 2000 HS and PG and
APM Permacast MS-10,000 with ConShield, applied at the required one inch thick
application, is the only product approved which does not require a subsequent
epoxy coating.
7. Other approved materials are located on SAWS website under SAWS Approved
Products List. The list is periodically updated and should be checked by Contractor
prior to start of construction.
8. For reconstructed manholes; first, apply a combination of cementitious coatings
followed by an approved epoxy coating with the cementitious coating first. Kerneos
SewperCoat 2000 HS and PG and APM Permacast MS-10,000 with ConShield,
applied at the required one inch thick application, is the only product approved
which does not require a subsequent epoxy coating.
9. Other approved materials are located on SAWS website under SAWS Approved
Products List. The list is periodically updated and should be checked by Contractor
prior to start of construction.
10. New Manholes shall be precast manholes and shall have an antimicrobial additive
introduced to the concrete mix in order to provide protection against Microbial
Induced Corrosion (MIC).
a. The liquid antimicrobial additive shall be an EPA registered material and
the registration number shall be submitted for approval prior to use in the
project.
b. Manufacturer shall also provide a State of Texas registration for the
antimicrobial.
c. Manufacturer shall be approved by SAWS Products Standard Committee
and be on the APL
d. The antibacterial additive shall be used to render the concrete uninhabitable
for acid producing bacterial growth.
e. The antimicrobial shall only be used by precast producers that have been
certified by the manufacturer of the antimicrobial additive.
f. Dosage of the antimicrobial shall be per manufacturer’s recommendations.
g. A ferrous oxide tinting agent shall be used to identify all antimicrobial
concrete precast, and shall be dosed per manufacturer’s recommendations
producing a terracotta tint to the cured concrete.
852.5 CONSTRUCTION:
1. Manholes shall be constructed of materials and workmanship as described by these
specifications, at such places shown in the contract documents or as designated by
the Engineer, and in conformity with the typical details and sketches shown.
2. Unless otherwise shown in the contract documents or approved by the Engineer,
standard sanitary sewer manholes shall be constructed with influent and effluent
piping less than or equal to 24 inches in diameter with precast reinforced concrete
manhole sections.
San Antonio Water System Standard Specifications for Construction
852-5 August 2019 852 sanitary sewer manhole.docx
3. A standard sanitary sewer manhole shall be a single entrance cylindrical structure,
having a minimum internal diameter of 4 feet between the cone and base sections.
4. The base of the structure shall include the load bearing portion beneath and exterior
of the structure, invert channels and the fill or bench portions adjacent to the lower
sewer pipes within the structure.
5. The maximum vertical height of the diameter adjustment section or cone shall be
36 inches.
a. Adjustment of throat rings may be used for final elevation adjustment of
the manhole ring and cover.
b. Concrete encasement of the manhole’s ring shall be as shown in the DD-
852 Standard Drawing Series.
c. Ring and cover shall be attached to the diameter adjustment flat top section
or cone.
d. Manholes which differ from the above description shall be governed by
Specification Item No. 850, "Sanitary Sewer Structures."
6. An internal drop manhole shall be required, when sewer lines enter a manhole more
than 24 inches above the manhole invert.
7. An external drop manhole shall be provided for a sewer entering a manhole more
than 30 inches above the invert.
8. Internal drop manholes will require prior approval by the SAWS Engineering
Director.
9. Footings or bases of manholes shall be a minimum of 6 inches in depth below the
bottom of the pipe.
10. All invert channels shall be constructed and shaped accurately so as to be smooth,
uniform and cause minimum resistance to flow.
11. The bench shall be finished smooth with a slope of ½ inch per foot from the
manhole walls to the edges of the invert.
12. The top half of all sewer pipes within the invert channel or bench zone shall be
removed flush to the inside manhole walls.
13. Joints on sewer pipes shall not be cast or constructed within the wall sections of
manholes.
14. Concrete cradles shall be required for new pre-cast manholes.
15. Concrete cradles shall extend beyond the outside walls of the manhole a minimum
of 36 inches.
16. Voids between exterior pipe walls and manhole walls at all pipe connections in
manholes shall be filled with a non-shrink grout, as specified above, or as approved
by the Engineer, or as shown in the contract documents and inspected prior to
backfilling.
17. Where connections to existing manholes are required, the adjacent pipe bedding
shall be prepared to proper grade, the existing manhole neatly cored and the new
pipe inserted so that the end is projecting 2 inches from the inside wall.
18. The invert shall then be reshaped to properly channel new flows.
19. Debris of any kind shall be kept out of new or existing manholes or mains.
20. Joints between cones, risers, adjustment rings, flat tops, and between the ductile
San Antonio Water System Standard Specifications for Construction
852-6 August 2019 852 sanitary sewer manhole.docx
cast iron ring and the uppermost adjustment ring or flat top, as applicable, shall be
thoroughly sealed in accordance with manufacturer’s recommendations with
adhesive bitumastic products as specified above.
21. Where precast concrete risers are used, any gaps in the outer joint surfaces shall be
additionally coated with non-shrink grout to a minimum thickness of ¼ inch.
22. All manhole rings shall be encased with 4,000 psi reinforced concrete as shown in
the contract documents or as approved by the Engineer.
a. Concrete manhole ring encasement shall extend 6 inches below the top of
the cone and have a minimum width when measured at the manhole ring of
1 foot. The surface of the encasement shall be flush with the top of the
manhole ring.
23. All new manholes shall be encased with a minimum of 12 inches thickness of
flowable fill to one foot above the cone section. See DD-852 drawing series.
852.6 TESTING: The Contractor shall notify Inspector and Engineer 48 hours prior to beginning
of manhole testing and only after a successful pretest has been performed.
1. Contractor is to be prepared to test if coordinated with Inspector. Fines maybe
assessed if Contractor cancels or delays testing.
2. The Contractor shall perform the testing for all sanitary sewer manholes in
accordance with the following:
3. All manholes must pass a leakage test.
4. The contractor shall test each manhole (after assembly and backfilling) for leakage,
separate and independent of all other sanitary sewer piping, by means of either a
hydrostatic test, vacuum test, or other methods approved by the Engineer.
5. The Contractor is hereby instructed to conduct either of the two identified tests in
the following manner:
a. Hydrostatic testing shall be conducted by utilizing approved plugs to seal
all influent and effluent pipes in the manhole and filling the manhole to the
top of the cone with water.
(1) Additional water may be added over a 24-hour period to compensate
for absorption and evaporation losses.
(2) At the conclusion of the 24- hour saturation period, the manhole
shall be filled to the top and observed.
(3) Any measureable loss within a 30 minute period shall be considered
an unsuccessful test and thus require the Contractor to assess the
needed repairs, perform such repairs (subject to the approval of the
Engineer), and notify the Inspector when the retest will be
performed.
(4) All effort, materials, or other costs shall be solely at the Contractor’s
expense.
b. Vacuum Testing: Manholes shall be tested after construction/ installation
and backfilling with all connections (existing and/or proposed) in place.
(1) Drop- connections and gas sealing connections shall be installed prior
to testing.
San Antonio Water System Standard Specifications for Construction
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(2) The lines entering the manhole shall be temporarily plugged with
the plugs braced to prevent them from being drawn into the
manhole.
(3) The plugs shall be installed in the lines beyond drop connections,
gas sealing connections, etc.
(4) Prior to performing the test, the Contractor shall plug all lift holes
and exterior joints with a non-shrink grout and plug all pipes
entering the manhole.
(5) Only a cementitious coating maybe applied.
(6) Contractor shall use a minimum 60 inch-lb. torque wrench to tighten
the external clamps that secure the test cover to the top of the
manhole.
(7) The test head shall be inflated in accordance with the manufacturer's
recommendations.
(8) A vacuum of 10 inches of mercury shall be drawn, and the vacuum
pump will be turned off.
(9) With the valve closed, the level vacuum shall be read after the
required test time.
(10) If the drop in the level is less than 1 inch of mercury (final vacuum
greater than 9 inches of mercury), the manhole will have passed the
vacuum test.
(11) The required test time is 2 minutes.
c. Acceptance: Any manhole which fails the initial test must be repaired with
a non-shrink grout or other suitable material based on the material of which
the manhole is constructed.
d. The manhole shall be retested as described above until a successful test
is attained.
e. After a successful test, the temporary plugs will be removed.
f. To ensure that the plugs have been removed, Contractor shall only do so in
the presence of the Inspector.
(1) Repairs to Existing Manholes: Any existing manhole which fails to
pass the hydrostatic/vacuum test shall be closely examined by the
Inspector and the Contractor to determine if the manhole can be
repaired.
g. Thereafter, the Contractor shall either repair or remove and replace the
manhole as directed.
h. The manhole shall then be retested and coated with a SAWS- approved
sewer coating as stated above.
i. The Owner may elect to simply remove and replace the existing manhole
with a new one.
j. Any manhole excavated for repairs or excavated for tie in, shall be
backfilled with flowable fill up to 1 foot above the top of the cone.
(1) Holiday Testing: Inspect each sanitary sewer manhole using high-
voltage holiday detection equipment.
San Antonio Water System Standard Specifications for Construction
852-8 August 2019 852 sanitary sewer manhole.docx
k. All detected holidays shall be marked and repaired by abrading the coating
surface with grit disk paper, or other hand tooling method.
l. After abrading and cleaning, additional protective coating material shall be
applied to the repair area.
m. All touch-up repair procedures shall follow the protective coating
manufacturer’s recommendations
5. If a sanitary manhole fails to pass one of the above tests, it shall be repaired in
accordance with the manufacturer’s recommendations and re- tested.
6. It shall not be accepted until it passes all tests.
7. All repairs and re- testing and replacement shall be at no additional cost to SAWS.
852.7 MEASUREMENT: Sanitary sewer manholes (0 to 6 feet deep) as designated in the
contract documents shall be measured as the total number of such manholes constructed,
including those exceeding 6 feet in depth from the lowest invert elevation to the top of the
ring.
1. Manholes deeper than 6 feet shall be measured by the number of vertical feet in
excess of 6 feet.
852.8 PAYMENT:
1. Sanitary sewer manholes shall be paid at the contract unit price bid for each such
manhole at the following milestones:
a. Milestone 1: Manhole setting to include for each such manhole, which price
shall be full compensation for setting manhole base setting to include
concrete base encasement with steel reinforcements as described in this
specification. After curing of concrete manhole flowline elevation shall be
verified and approved by engineer of record prior to payment.
b. Milestone 2: Manhole riser installation: All manhole risers and cone
sections shall be paid at the contract unit price bid for each such manhole
riser, which price shall be full compensation for all remaining sections,
flowable fill (up to 1 foot above the bottom of the cone section), drop pipes,
saw cutting of surfaces as required, reinforced concrete, diversion of flow,
fittings, labor, tools, equipment, tees, wyes, and incidentals trench
protection, special shoring and disposal of material excavated, and for
furnishing and placing all materials, all testing, necessary to complete the
work prior to payment.
c. Milestone 3: Sanitary Sewer Manhole Encasement and Testing: This pay
item includes manhole concrete encasement and rebar, HDPE throat rings,
UV stabilized polyethylene liner I/I barrier, ring and cover.
2. Extra depth manholes shall be paid for at the contract unit price bid per
vertical foot as measured above.
3. Concrete cradles for pipes shall be measured and paid for at the contract
unit price bid as provided for in Specification Item No. 858, "Concrete
Encasement, Cradles, Saddles and Collars."
4. Gravel subgrade filler for manholes shall not be measured separately for payment.
San Antonio Water System Standard Specifications for Construction
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Pay Item Description Units
852.6.1.a Milestone 1: Manhole setting Each
852.6.1.b Milestone 2: Installation and
Acceptance Testing
Each
852.6.1.c Milestone 3: Manhole Encasement Each
853.6.2 Manholes deeper than 6 feet Vertical feet.
End of Specification